• Journal of applied mathematics & informatics
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• v.41 no.2
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• pp.387-400
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• 2023

The purpose of the present paper is to obtain some subordination and superordination preserving properties with the sandwich-type theorems for multivalent functions in the open unit disk associated with Srivastava-Attiya operator. Moreover, applications for integral operators are also considered.

• Korean Journal of Mathematics
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• v.30 no.1
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• pp.81-90
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• 2022

The present investigation is concerned with the estimation of initial coefficients, Fekete-Szegö inequality, second Hankel determinants, Zalcman functionals and third Hankel determinants for certain subclasses of Sakaguchi type functions defined with subordination in the open unit disc E = {z ∈ ℂ : |z| < 1}. The results derived in this paper will pave the way for the further study in this direction.

• Kyungpook Mathematical Journal
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• v.63 no.2
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• pp.225-234
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• 2023

In this paper, we use the use the linear operator ʒ^x_τ,σ(u, v, y)𝔣(z) and the concept of the subordination to analyse the general class of all analytic univalent functions. Our main results are implication properties between the classes of such functions and the application of these properties to special cases.

• Journal of Applied and Pure Mathematics
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• v.5 no.3_4
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• pp.223-236
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• 2023

In the present paper, we investigate the subordination and superordination implications for a class of certain nonlinear integral operators defined on the space of normalized analytic functions in the open unit disk. The sandwich-type theorem for these integral operators is also presented. Further, we extend some results given earlier as special cases of the main results presented here.

• Journal of the Korean Mathematical Society
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• v.43 no.2
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• pp.311-322
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• 2006

For the Briot-Bouquet differential equations of the form given in [1] $${{\mu}(z)+\frac {z{\mu}'(z)}{z\frac {f'(z)}{f(z)}\[\alpha{\mu}(z)+\beta]}=g(z)$$ we can reduce them to $${{\mu}(z)+F(z)\frac {v'(z)}{v(z)}=h(z)$$ where $$v(z)=\alpha{\mu}(z)+\beta,\;h(z)={\alpha}g(z)+\beta\;and\;F(z)=f(z)/f'(z)$$. In this paper we are going to give conditions in order that if u and v satisfy, respectively, the equations (1) $${{\mu}(z)+F(z)\frac {v'(z)}{v(z)}=h(z)$$, $${{\mu}(z)+G(z)\frac {v'(z)}{v(z)}=g(z)$$ with certain conditions on the functions F and G applying the concept of strong subordination $g\;\prec\;\prec\;h$ given in [2] by the author, implies that $v\;\prec\;{\mu},\;where\;\prec$ indicates subordination.

• Communications of the Korean Mathematical Society
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• v.37 no.2
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• pp.445-454
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• 2022

Using the concept of the strong differential subordination introduced in [2], we find conditions on the functions θ, 𝜑, G, F such that the first order strong subordination θ(p(z)) + $\frac{G(\xi)}{\xi}$zp'(z)𝜑(p(z)) ≺≺ θ(q(z)) + F(z)q'(z)𝜑(q(z), implies p(z) ≺ q(z), where p(z), q(z) are analytic functions in the open unit disk 𝔻 with p(0) = q(0). Corollaries and examples of the main results are also considered, some of which extend and improve the results obtained in [1].

• Honam Mathematical Journal
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• v.46 no.1
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• pp.120-135
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• 2024

A normalized analytic function f, defined on the unit disk 𝔻, is starlike of reciprocal order α > 1 if the real part of f(z)/(zf'(z)) is less than α for all z ∈ 𝔻. By utilizing the theory of differential subordination, we establish several sufficient conditions for analytic functions defined on 𝔻 to be starlike of reciprocal order. Additionally, we investigate the conditions under which the function f(z)/(zf'(z)) is subordinate to the function 1 + (α - 1)z. This subordination, in turn, is sufficient for the function f to be starlike of reciprocal order α > 1.

• Communications of the Korean Mathematical Society
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• v.13 no.1
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• pp.159-170
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• 1998

In this paper, we extend Burkholder's exponential inequality for a strong subordinate of a nonnegative bounded submartingale.

• Communications of the Korean Mathematical Society
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• v.22 no.1
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• pp.19-26
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• 2007

In this paper we derive certain sufficient conditions for star-likeness and strongly-starlikeness of analytic functions in U, by using the method of differential subordination.

• Honam Mathematical Journal
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• v.21 no.1
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• pp.139-147
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• 1999

In this paper we generalize the definition of strongly close-to-convex functions by using the functions g(z) of bounded boundary rotation and investigate the distortion and rotation theorem, coefficient inequalities, invariance property and inclusion relation for the new class $G_{k}[A,\;B]$.